Johnny's homebuilt 8080 CPU corner (and other stuff, maybe)
8080 CPU, built entirely by DTL-technology
This is my latest design of the CPU REGISTERS - a SLICE.
This one shown here is a prototype and will be used for bit 0 (after debugging). And I found a couple.
16 of these boards, plus 4 more ones for MUX-ing and 3-State buffering, is all there is to build the 8080 registers.
Update Jun 18, 2016 - All 16 register slices has been soldered and is up and running.
The MUX is fairly simple, just as in the 74LS245 there is 2 crossing gates with some control logic.
My 3-State buffer is based on 74LS366/368. Some component values is different (not by much) and the control logic is merley a single NOT gate (not shown here).
As long as CONTROL is HIGH the output i active. Pull it LOW and the output goes into 3-State.
The 74LS366 is an inverting buffer. I don't want that so I have put in an inverter (Q43 in the schematic below) to compensate.
At the time, it was easier than to bredboard the 74LS365 (non inverting).
Here is the "blueprint".
To join the Homebuilt CPUs ring, drop me a line, mentioning your page's URL. I'll then add it to the list.
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Note: The ring is chartered for projects that include a home-built CPU. It can emulate a commercial part, that′s OK.
But actually using that commercial CPU doesn′t rate. Likewise, the project must have been at least partially built: pure paper designs don′t rate either.
It can be built using any technology you like, from relays to FPGAs.